I. Field of the Invention
The present invention relates generally to a multi-fixture rack system. More particularly, the present invention relates to a multi-fixture rack system for use with a universal vacuum and clamp set-up fixture for measuring a wide variety of different parts.
II. Description of the Prior Art
Newly developed automated factories having automated assembly lines provide for an automated inspection process of the manufactured part assembled in the factory. Typically, an automated inspection process is used to assure quality control of mass produced parts. Inspection of parts may also be required where high levels of tolerance of a part are necessary, such as in aeronautical parts.
Automated inspection equipment may take the form of a computer controlled video camera placed above an assembly line setting. As the parts travel on the assembly line below the camera, a computer reads the picture to determine if a random part is within standard tolerance.
Other automated inspection equipment may include the use of coordinate measuring machines utilizing a fixed work surface for placement of the piece to be measured. A part is oriented on the work surface and a measuring probe attached to a coordinate measuring machine measures the part and compares it with standard acceptable tolerances.
An example of automated inspection equipment of this general type is disclosed in U.S. Pat. No. 4,805,887. The device disclosed in this patent includes the utilization of a perforated work surface having a coordinate system corresponding to the perforations. A variety of clamps and vacuum clamp holders may be placed in the perforations of the plate and are used to support the piece to be measured. A vacuum source directs a vacuum to the vacuum clamp holders. The vacuum clamp holders are equipped with flexible suction cup clamps which exert minimum distortion loads on the clamped parts.
Although this system provides a means for measuring a part without distorting the part by clamping, it does not provide for an error-free environment. In particular, the user may not be aware that the clamps and vacuum clamp holders are mislocated thereby giving a false reading to the measuring probe. Further, only one part may be measured at a time. For example, if an assembly line produces a multiplicity of parts, as is usually the case, the present measuring system only provides for measurement of one part. Therefore, several measuring devices must be set up to enable several different parts to be measured or the user must break down and reset the clamp set-up when measuring different parts. This is a time-consuming operation which may cause great errors if the operator fails to perform each set-up precisely.